


suddenly seeing

by sharkfish



Category: Supernatural
Genre: Alternate Universe - Aliens, Alternate Universe - Roommates/Housemates, Cecaelias, M/M, Marijuana, Recreational Drug Use, Tentacles, mostly just smut, octo cas
Language: English
Status: Completed
Published: 2020-11-28
Updated: 2020-11-28
Packaged: 2021-03-09 23:21:37
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,618
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/27764413
Author URL: https://archiveofourown.org/users/sharkfish/pseuds/sharkfish
Summary: Cas stares at his own tentacle as he runs the tip up Dean’s neck, slides it along his jawline, traces the rise of his cheekbone. No one touches Dean like this.“It’s strange,” Cas says. “Suddenly seeing something beautiful where you couldn’t in the past.”
Relationships: Castiel/Dean Winchester
Comments: 42
Kudos: 274
Collections: Tentacles





	suddenly seeing

**Author's Note:**

> with gratitude to oriana and all the octo weirdos out there

Dean does not have a crush on his roommate. 

Which is why this conversation is not a big deal. It’s just the kind of stupid things you talk about with a newish friend when both of you’re both cross-faded and slung across the cushions like nothing has ever been as comfortable as this couch that came from some guy on craigslist. 

Cas is touching him. Dean has always thought it’s stupid how little humans touch each other outside of a few specific contexts, and always appreciated that cecaelia are so tactile. Dean’s used to that, but what he’s not used to is Cas running his tentacles aimlessly over Dean and saying, “I didn’t know you’d been with cecaelia.” 

Dean chokes on his beer. Earlier, the house had been full of friends and Jo had made a stupid joke, waggling eyebrows included, about Dean and Benny’s romantic — and sexual — history. Dean’s pretty sure she only did it because she knew Cas would overhear, because she thinks Dean has a crush on his roommate. 

“Um,” Dean says intelligently. “Didn’t know that was something I should’ve told you.” 

“Of course not,” Cas says. One of his tentacles tickles along the bare skin at Dean’s hip where his shirt is riding up and he’s slumping down further into the couch. “I was just surprised. Humans don’t  _ date  _ cecaelia.” 

“Some of us do, apparently,” Dean says, grinning. Cas starts giggling uncontrollably, pressing his face into the couch cushion to try to hide it. “Cas, that wasn’t even a joke.” 

Cas laughs harder, muffled, and the skin of his tentacles rolls gradients of color from top down. Dean never quite figured out how to read cecaelian color language, but he knows this is one of his favorite messages from Cas. Whatever the hell it says, it only shows up during moments of carefree joy. Dean squeezes the tentacle toying with the collar of his shirt. 

“I’m sorry, I’m just — really, really — really high.” Cas turns his head so Dean can see one of his eyes. “And I’ve never been attracted to a human before.” 

“There’s no reason to be,” Dean says, and it’s lucky he doesn’t have a crush on his roommate or he might be crestfallen. 

Cas stares at his own tentacle as he runs the tip up Dean’s neck, slides it along his jawline, traces the rise of his cheekbone. No one touches Dean like this. 

“It’s strange,” Cas says. “Suddenly seeing something beautiful where you couldn’t in the past.” 

“Yeah,” Dean says, without having any idea what he’s responding to, because he’s wholly focused on where he’s being touched. 

“You are very, very beautiful,” Cas says. 

Dean blinks and rewinds. “Wait, me? But you just said — and I’m human.” 

Cas’s tentacles take on this flush of blue that is the cecaelian version of a blush. “I never thought I was interested in humans, until I met you. But everyone knows humans just use us for bragging rights.” 

Other than discussing furniture adjustments when Cas moved in and the occasional laughing debate on whether legs or tentacles are better — tentacles, obviously, but Dean keeps trying to argue, however weakly, for legs — they don’t talk about this. Benny isn’t the kind of guy who worries himself over that kind of thing, but Charlie and Dean have had a lot of conversations about human supremacism and the rift between the two species. 

“A lot of humans are horrible,” Dean says. “I’m tryin’ not to be.” 

Cas takes a careful breath, and then the tentacle that was touching Dean’s cheek is tracing along his bottom lip. “I would like,” Cas says, breaths still measured, “to kiss you.” 

“Me too,” Dean says. 

Cas smiles, canines a little too sharp to be human, and leans closer to press their mouths together. A quiet, gentle kiss, a short pause like a question, and then the next kiss is  _ more.  _ Dean slides his hand into Cas’s hair, pulls him closer, and is suddenly surrounded by tentacles. It freaked him out the first time he was with a cecaelia — like the sharp canines, cecaelia’s ability to touch everywhere at once is alien and disconcerting.

Cas is an amazing kisser and the weed makes kissing even better. It seems stupid that they haven’t done this until now. It’s stupid that Dean’s been trying to make himself believe that he doesn’t have any feelings for Cas. 

“Will you go on a date with me?” Cas asks. 

“You can’t kiss me like that and then expect me to answer questions,” Dean says, grinning. “But — yeah. Obviously.” 

“I put out even before the first date,” Cas says. “Just something you should know about me.” 

Dean’s eyes widen and Cas’s solemn expression breaks, and then they’re both giggling, Cas’s tentacles tightening where they’re holding Dean. “I usually wait for marriage,” Dean says, trying to play it cool, “but I can make an exception for you. Take me to your bed, Casanova.” 

“You know where it is.” 

“You’re bad at romance,” Dean says, rolling his eyes before he gets up. Cas follows him down the hall, nearly silent on the carpet. 

Cas’s bed is fucking humongous. It’s why Dean didn’t mind letting him have the master — Dean has never met someone who has a bed better than his before. It isn’t made, sheets still rumpled. He climbs in and collapses on his belly, face shoved into a pillow. “This is amazing,” Dean says, muffled. “Jesus, if this were my bed, I would never leave.” 

“I’ll keep that in mind,” Cas says. The bed dips as he joins Dean. One of his tentacles slides under the back of Dean’s shirt. 

The soft pops of Cas’s suckers on his skin feel like kisses. Dean turns to face Cas, murmuring, “That feels good.” 

Cas’s touches grow bolder, a tentacle sliding up Dean’s stomach to brush across one of his nipples. “What else feels good?” Cas says, suddenly closer, within kissing range. Dean reaches for him, gripping one of his tentacles as it snakes around him, and Cas’s breath catches. 

“Kissing,” Dean says, scooting closer to give Cas a soft kiss. “Touching you.” Dean wraps his arm around Cas’s middle, rucks up his tunic to slide a hand underneath, press flat against the small of his back where his skin goes from smooth to velvet. “Sucking your cock.” Cas’s tentacles tighten around him as Dean noses under his jaw, leaves wet kisses down the column of his throat. “Putting my mouth all over you.” Cas shudders and Dean whispers against his collarbone, “How does that sound?” 

“I could be — ah — amenable to that,” Cas says. 

“‘Amenable,’” Dean repeats, then starts giggling helplessly, entirely unsuccessful in trying to hide it against Cas’s tunic. Cas’s responding laugh is a thunder-rumble in his chest, and he wiggles in delight all around Dean, something so adorable that Dean will never admit the way it warms him, even when his heart is the loneliest. 

“Stop that,” Cas says, still grinning. “You’re not allowed to make fun of me in my own bed.” 

“I’ll do what I want, thank you,” Dean says, then steals a kiss that goes from a giggling press of mouths to hot and deep, Cas’s teeth scraping along Dean’s lower lip as they part. “Take off your clothes.” 

At the same time that Cas is pulling off his tunic, his tentacles are tugging at Dean’s clothes, manhandling him around until Dean is naked, cradled in his touch. “Jesus  _ Christ,”  _ Dean says. He reaches for Cas, but Cas grabs his hands and pins them to the bed, holding him completely immobile with his tentacles, the delicate suckers latching and letting go in feather-light kisses. 

Dean pouts and says, “No fair.” 

“Oh?” Cas says, running his fingertips along the underside of Dean’s cock, straining hard against his stomach. “You want me to stop?” 

Dean relaxes into his hold, unable to keep from grinning again. “Nope, I’m good. Continue.” 

Cas laughs then presses closer, nipping at the side of Dean’s neck, then lower, goosebumps breaking out surrounding the pinch of Cas’s teeth. “You,” Cas says, between wet kisses down Dean’s chest, “are so beautiful.” 

“You,” Dean says back, between gasps, “are fucking hot. And smart. And — Jesus, do that again.” 

One of Cas’s tentacles suck on the inside of Dean’s thigh, and then again, hard enough to pull bruises to the surface. 

Being in bed with a cecaelia is overwhelming, a dizzying, back-arching array of touch, velvet smooth tentacles and rubbery suckers and calloused hands tracing over every inch of Dean’s skin. Dean didn’t get to see, but Cas’s cock extended, pressed hard and hot against Dean’s hip, wet with precome. 

Dean tilts his chin to nuzzle against the tentacle draped over his shoulder, and it curls around his neck to stop him from moving. Dean stops breathing, arousal spreading from that point downwards.

But Cas pulls it away with a jerk and says, “Fuck, I’m sorry. I wasn’t — I wouldn’t —” 

“I know,” Dean says. “I kinda liked it anyway.” 

“Oh?” Cas says, a sucker pulling gently at the side of Dean’s neck. “I didn’t know you were kinky.” 

“Are you surprised?” 

“Not particularly, no,” Cas says, flashing Dean a grin while his hands smooth down Dean’s body, stopping to cup around his hips, a little soft from too many nights of munchies. It’s not fair that Cas was there for most of the recent ones and still looks like he was chiseled out of marble. 

“Let me touch you,” Dean says. It comes out a little softer than he meant it to, and as soon as Cas releases his wrists, Dean pulls him down into a hot kiss. 

Dean loops one arm around Cas’s neck to hold him close, the other exploring Cas’s chest and stomach and eventually finding the hard silk of Cas’s cock. Cas groans into Dean’s mouth at the first stroke but doesn’t break the kiss until Dean jerks him back by the hair. Cas gives a little growl and Dean laughs at his disgruntlement. 

“Was just gonna ask if you want to fuck me,” Dean says. “And if you have —”

There’s a bang as the drawer from Cas’s nightstand tumbles to the ground from him pulling it too hard, and Dean laughs again while Cas mutters, “Oh, shut the fuck up.” 

Lube and condoms are dropped on the bed by two different tentacles, and Dean snatches the bottle before it can roll off. “I can do it.” 

“You will not,” Cas says, pinning Dean’s hands down again. 

“You’re so bossy,” Dean says. “But I kinda like that, too.” 

“Duly noted.” 

Dean squirms, not because he actually wants to get away but because he undersold how much he likes Cas holding him down and then giving him a certain kind of look as if to say,  _ Behave.  _ Cas liberally wets his fingers and gives Dean’s cock a few loose strokes, biting his lip as he watches himself do it, before his touch trails further downward. The tentacles around Dean’s thighs tighten and pull them them further apart. “Jesus,” Dean whispers, distinctly aware of the precome pooling on his stomach. 

“I want to make some sort of blasphemic joke,” Cas says, still watching as his fingertips circle Dean’s hole, “but my brain stopped functioning a few minutes ago.” 

“We can fill it in later,” Dean says, doing his best to arch his hips like he can rush Cas onward. 

Cas decides to play nice at least and slides a finger into Dean, slow and slick. Cas makes a soft noise of surprise, though Dean isn’t sure at what and he doesn’t manage to ask before Cas steals his breath in a hard, biting kiss, and then another, as he works two fingers into him, torturously slow. 

“Stop teasing me,” Dean says against Cas’s mouth, breaking off into a gasp as Cas twists his fingers on the way out. “I want to feel you, c’mon.” 

“Like this, or is there another position you prefer?”

“Like this, doing a handstand — dude, I don’t care, come on.” 

“Shocker,” Cas says, smiling down at Dean. “You’re as impatient in bed as in the rest of life.” 

“No one is entirely perfect,” Dean says. He watches with greedy eyes while Cas rips open the condom and slides it on. Cas’s cock is so  _ pretty,  _ tense in his hand, and Dean can’t wait to feel it stretch inside him. 

Cas’s teeth are danger-sharp catching on the tender skin just under Dean’s ear as he slides in bit by bit. Cas doesn’t make a sound, but the tentacles wrapped around Dean’s limbs seize and then suck again in the harsh rhythm of Cas’s breathing.

“You’re ok,” Dean murmurs. “Feels good.” 

Cas nods against his neck and Dean feels him let go, not just the long exhale but the sudden movement of his cock, touching inside Dean just as surely as his fingers did, rubbing and searching in a way human cocks can’t. 

“Holy fuck,” Dean gasps, and then, “Right there, right there.” 

“Here?” Cas asks, pressing again, but withdraws as soon as Dean nods. 

“Dammit, Cas!” 

Cas giggles, muffled against Dean’s temple, and Dean squirms in the hold of his tentacles again. Petulant, Dean says, “I hate you.” 

“But you do like…” That press and rub again, and then the slow undulation as Cas sinks in all the way. 

“Jesus, yeah, that’s — Jesus,” Dean pants. “Holy fuck.” 

“You mentioned that,” Cas says, and he kisses Dean, deep and slow this time, loosening his hold so Dean’s hands can pull free again. 

Dean slides his hands down Cas’s back and below his waist, gripping a tentacle in each hand to pull him closer, closer, and feels Cas’s moan reverberate through his chest. Something about that — just that rumble — has Dean flying higher than Cas covering him in touch. 

The end of one of Cas’s tentacles wraps hesitantly around Dean’s cock. “Show me,” he says, eyes bright. 

Dean wraps his hand around the outside of Cas’s tentacle the best he can, squeezes just a little tighter, guides his strokes until he loses the ability to do anything but just take Cas’s touches, all around and inside of him. 

“Oh god, oh god — oh —” A sucker latches onto his balls and he comes so hard he’s dizzy with it, hips raised to take Cas deeper. Cas’s breath catches and he goes tense inside of Dean, coming in hard pulses as Dean clenches around him.

Slowly, Cas’s tentacles uncoil from around Dean, the places where his suckers pulled tender in the cool air. Dean’s eyes fall close as he gasps for breath, and then Cas is laying next to him, one of his tentacles smearing across the come on Dean’s stomach. 

“So,” Dean says after a long silence, glad his voice comes out even. “How was your first time with a human?” 

“Satisfactory,” Cas says. Dean’s eyes open in alarm but Cas is smiling openly at him, tentacles a rolling rainbow gradient, almost glittering in the glow of the lamp. 

“You’re an asshole.” 

“An asshole who’s taking you to dinner tomorrow.” 

“Or we could eat in and I could spend more time with your bed, the love of my life.” Something goes tight in Cas’s expression, and Dean hurries to say, “Kidding. You’re taking me on a real date.” 

Cas smiles, gives Dean a soft kiss, wraps all of his tentacles around him to hold him close. “Stay tonight.” 

“Yeah, of course. You’re not getting rid of me now.” 

All of Cas’s suckers pull against Dean’s skin and then relax, both of them smiling so big it hurts, and Dean admits that he might have a bit of a crush on his roommate. 

**Author's Note:**

> [sharkfish on tumblr](http://sharkfish.tumblr.com)
> 
> [rebloggable tumblr post](https://sharkfish.tumblr.com/post/636066953782509568/suddenly-seeing-on-ao3-octo-cas-roommates)
> 
> i'm sorry i'm so terrible at answering comments, but please know that every single one is so precious to me and keeps me going on the rough days. <3 thank you for being here!!


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